Algal biofuel production can reach the ocean, study says

If the research holds up in practice, production of algae biofuels can expand from tanks and ponds to the vast ocean. And by using non-potable ocean or brackish water for petroleum substitutes, increasingly scarce fresh water can be conserved for people.

The scientists genetically engineered marine algae to make valuable industrial enzymes in addition to oil. This feat had been performed in freshwater algae but not in marine species, said UC San Diego researcher Stephen Mayfield, who led the study.

They experimented on a species of algae named Dunaliella tertiolecta, which has a high oil content. They inserted five genes, allowing production of five kinds of industrial enzymes.

“What we showed is that we could do the genetic engineering that’s going to be required to really get costs down,” Mayfield said.

San Diego has become a major center of algae biofuel research. It includes companies such as Sapphire Energy and Synthetic Genomics, and researchers such as Mayfield, also a scientific founder of Sapphire Energy.

A report from the San Diego Association of Governments found that 466 people in San Diego work in the algal biofuels industry, providing more than $41 million in payroll and $80.9 million in economic activity for the region in 2011. In 2010, 410 people worked in the field, and 215 in 2009.

Algal biofuels must compete not only against fossil fuels, but against other crops, including corn and nonfood “cellulosic” plant material for ethanol, and the jatropha bush, which produces oily seeds. All of these biofuels face limitations that prevent their large-scale adoption anytime soon.

The key to making algae more competitive as a biofuel is to get more value out of all the algae, Mayfield said. Oil constitutes just 30 percent to 40 percent of the total mass of the algae.

“One of the ideas that people had for monetizing (the remaining part) was to make high-value proteins in it,” Mayfield said. “We’ve shown we can do that by expressing industrial enzymes.”

Industrial enzymes are used in all sorts of manufacturing products. One of the best-known categories are cellulases, used to soften “stonewashed” jeans. Producing this cellulase demonstrated proof of principle, Mayfield said.

The genetic engineering technology can also be used to increase the value of biofuels made by the algae, Mayfield said.

“That’s not what we showed in this paper; we simply showed we can make industrial enzymes,” he said. “But if you can do those, you can do the other.”

In addition, the rest of the algae could be used as a supplement to animal feed, the study stated.

Cultivation of ocean algae can take place over a much wider area than freshwater algae, Mayfield said, including land unusable for other crops because it has too much salt. Algae cultivated on such land wouldn’t compete with food production, and would not use fresh water, which has become increasingly scarce as demand rises.